If you have the M10 (SP) Submachine Gun this level is a quite a bit easier. If you haven't developed it yet, play some Ops while you put your R & D team to work on the M10.

At the start of the level, turn around and walk east and then north. You should be able to see two soldiers to the west. Approach the nearest one and hold him up (hold L to pull your weapon out and walk up to his back). Whisk him away with the Fulton. Now, shoot an Mk. 22 round into the guard on the upper level and head for the ladder in the south.

Jump down the ladder and follow the passage until you come to a Prisoner. Use the Fulton on him and then stand at the north end of the passage. A Kidnapper Drone patrols the trench here. Wait for it to pas you and make a dash for the west side OR, switch on auto-aim and use your silenced M10 (SP) to destroy the Kidnapper.

An explosion will rock the area and the soldiers will notice, but they won't raise an alarm past the green level. Lay low and wait for the green level to dissipate before continuing west.

Sneak below the guard and climb the ladder in the southwest. Hide behind a crate and wait until the solider turns away. You can grab him or just slip past.

A second soldier stands between you and the exit now. Wait for him to turn away and take him out with a hold-up or grab. Take the western elevator down below. Note: You will not be able to take the elevator if an alert has been sounded.

Small Maintenance Dock

Before doing anything, auto-aim at the Kidnapper in this area and take it out with your M10. Wait for the alert to subside and continue along the eastern perimeter of the level.

Sneak past the soldiers in the central area without taking them out. You do not want to attract attention here. In the northeast corner you'll find a Prisoner.

Wait behind the low wall for the guard in the northwest corner to turn away and snuff him out. You should now be able to sneak all the way to the south along the west side of the level.

In the southwest corner is yet another Prisoner. Grab him with the Fulton and then head back north. A staircase leads up to the second level of the western side of the area. From here you can make a dash for the western staircase.

Rooftop

Move to the west along the north side of the Rooftop. Wait for the lone patrolling soldier to approach you before grabbing him and silently putting him down. Now, aim your M10 at the Kidnapper buzzing around the central area. Take it out and you'll be able to sneak across the bridge easily.

Drop down the ladder and cross to the southern portion of the level. At the top of the ladder, quickly snuff out the soldier and keep your eye on the adjacent hallway.

When you get the chance, duck in and take out the final enemy. At the eastern end of the hallway is a final Prisoner. At the western end is the exit.